Update of post-processing states with variable sampling frequency according to the frame

Abstract

A method and apparatus are provided for updating post-processing states applied to a decoded audio signal. The method is such that, for a current decoded signal frame, sampled at a different sampling frequency from the preceding frame, it includes the following acts: obtaining a past decoded signal, stored for the preceding frame; re-sampling by interpolation of the past decoded signal obtained; using the re-sampled past decoded signal as a memory for post-processing the current frame. A decoding method is also provided, which includes updating post-processing states.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This Application is a Section 371 National Stage Application of International Application No. PCT / FR2015 / 051864, filed Jul. 6, 2015, the content of which is incorporated herein by reference in its entirety, and published as WO 2016 / 005690 on Jan. 14, 2016, not in English.FIELD OF THE DISCLOSURE[0002]The present invention relates to the processing of an audio frequency signal for transmitting or storing it. More particularly, the invention relates to an update of the post-processing states of a decoded audio frequency signal, when the sampling frequency varies from one signal frame to the other.[0003]The invention applies more particularly to the case of a decoding by linear prediction like CELP (“Code-Excited Linear Prediction”) type decoding. Linear prediction codecs, such as ACELP (“Algebraic Code-Excited Linear Prediction”) type codecs, are considered suitable for speech signals, the production of which they model well.BACKGROUND OF TH...

AI Technical Summary

Benefits of technology

The patent describes a technique for improving the quality of post-processing in video frames by adapting to the sampling frequency of the current frame. This helps to minimize complexity and reduce noise in the video. The technique involves using a post-processing module that uses a resampled past decoded signal as a memory for post-processing the current frame. This allows for better quality video in the transition frames between different sampling frequencies.

Problems solved by technology

This switching of frequencies between two frames may cause audible and troublesome artifacts, for several reasons.

This option does not produce a desirable result generally, since the noise which was post-filtered reappears abruptly on the transition frame.

With this method, the quality obtained is very mediocre.

The listening tests show that these solutions do not give a satisfactory quality.

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